TECHNICAL SPECIFICATIONS
Circuit Design: Based on the classic 4000 E132 "Orange Knob" Console EQ (inductor-emulation active circuit topology)
Format: 500 Series (VPR Alliance & GDIY 51X compatible)
EQ Type: 4-band semi-parametric with switchable Bell/Shelf
Gain Range: ±18 dB per band (with center detent for easy recall)
Input/Output: Balanced THAT 1246 input and THAT 1646 output stages
Power Requirements: Standard ±16 V DC (500 Series rack)
DETAILED FEATURES
Four-Band Precision Control:
◦ Low Band: 45 Hz – 450 Hz (switchable Shelf/Bell)
◦ Low-Mid Band: 0.2 kHz – 2 kHz (fully parametric with adjustable Q; gain dynamically scales with Q settings)
◦ High-Mid Band: 0.6 kHz – 6 kHz (fully parametric with adjustable Q; gain dynamically scales with Q settings)
◦ High Band: 1.4 kHz – 16 kHz (switchable Shelf/Bell)
Integrated Filters: Dedicated 80 Hz Low-Cut (24 dB/oct, modifiable) and 8 kHz High-Cut (24 dB/oct, modifiable) for instant signal cleanup
Premium Audio Path: High-headroom design featuring original WIMA capacitors and low-noise operational amplifiers
Professional Build Quality: Dual-layer PCB with immersion gold finish for maximum durability and easy soldering
WHAT'S INCLUDED IN THE KIT?
This is a full DIY kit including all parts for a successful build:
Powder-coated front panel with high-quality printing
All electronic components (resistors, capacitors, ICs, and THAT chips)
Full set of high-quality Sifam knobs
(Note: This product requires assembly and soldering skills. Interactive assembly guides are available in our Build Manuals section.)
Help yourself and others in the corresponding GDIY Help Thread